This invention relates to coppered azo dyestuffs containing a sulfonic acid group on one moiety of the molecule and a sulfonamido, sulfonyl or carboxamido group on the other. The invention also relates to various intermediate dyestuffs used in the preparation of these metallized dyes, to compositions, and to processes for preparing the metallized dyestuffs. Unmetallized monoazo dyestuffs containing a sulfonic acid group on the coupling component and a substituted sulfonamido group on the diazo component are known from U.S. Pat. No. 3,600,377. Although these known dyestuffs have good purity and brightness of shade and demonstrate good leveling properties, the light fastness of these compounds is not exceptional. Surprisingly, it has been found that coppering of the dyestuffs of the above-mentioned patent as well as other similar dyes produce compounds with drastically improved light fastness and remarkable brightness of shade on polyamide fibers.
Further, coppered monoazo dyestuffs containing a sulfonic group on the coupling component and an unsubstituted sulfonamido group on the diazo component are known from U.S. Pat. No. 3,511,827. These prior art dyestuffs, however, exhibit poor barre coverage as compared to the metallized dyestuffs of this invention. Furthermore, unmetallized and metallized (chromed or coppered) monoazo dyestuffs for wool containing a sulfonic group on the diazo component and an unsubstituted sulfonamido group on the coupling component are known from German Pat. No. 463800 (Friedlander Fortschritte der Teerfarben Publikation, Vol. 16, page 946). These known dyestuffs, however, have a markedly reduced affinity toward natural and especially synthetic polyamide fibers as compared to the dyestuffs of this invention.
It was further found that, as compared with the prior art dyestuffs as mentioned above, the metallized dyestuffs of this invention generally have a combination of good fastness properties, such as good light fastness, barre coverage, leveling properties and purity and brightness of their shades. These properties and especially good barre coverage are a very important consideration in the dyeing or printing of nylon in order to cover up irregularities. It was surprising to find that the compounds of the instant invention, in view of the drawbacks of the prior art compounds mentioned, showed remarkable brightness of shade, good over-all fastness properties and especially excellent light fastness and good barre coverage.